Rinnai HydraHeat® Hot Water Heat Pump

The future of hot water



The experts in water heaters and heat pumps have combined the technology of both to bring you a very clever solution - a Hot Water Heat Pump called HydraHeat®. Using the efficiency of heat pump technology, HydraHeat® will heat a home’s water while saving you up to 75% on your water heating costs*. The result is a far more cost-effective and more sustainable solution for the homes of tomorrow. Designed and built right here in New Zealand for Kiwi conditions, HydraHeat® is easy to install for any home. 

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Product Details

Up to 75% Savings on Hot Water Costs*
Provides highly efficient water heating, minimising energy consumption and lowering operating costs.
Dedicated to Sustainability
Powered by only 150g of high-efficiency R290 refrigerant with low Global Warming Potential and COP of 4.7.**
Renowned Quality
Crafted with exceptional quality by Rinnai New Zealand, the trusted name in total home living.
Designed and built in NZ
Specifically designed for New Zealand climatic conditions (from -10°C to +42°C), as well as coastal locations. Operates in full heat pump mode right down to -10°C without the need for electric boosting.
The inbuilt electric element guarantees a consistent and dependable supply of hot water, at all times.
Modular ‘Heat Pump Ready’ Design
Upgrade from a standalone HydraHeat® electric cylinder to Hot Water Heat Pump Technology by adding the HydraHeat® head unit.
Easy Servicing
Removable Heat Pump unit allows for easy servicing, and ensures uninterrupted supply of hot water.
Frost Protection
Built-in defrost and frost protection functions to handle colder climates.
NZ MEPS Compliant
MEPS (Minimum Energy Performance Standard) means less heat loss from unit and less energy use, resulting in a more efficient product. Not all Hot Water Heat Pumps in New Zealand are MEPS compliant.
5-year heat pump unit warranty and a 7-year cylinder warranty.
User Friendly Control Interface
Features OLED screen and six operation modes for versatility.
6 Operation Modes
Standard, Boost, Eco 55, Eco 50, High Usage, and Element Only.
Ideal for a Range of Residential Styles
Suitable for homes of 2–6 people. Plus an operating sound level of only 45dBA makes it suitable for a wide range of homes, including built-up residential areas.

* Compared with a standard hot water cylinder in Zone 5 (Auckland). Annual energy performance estimated according to AS/NZS4234:2008 and AS/NZS5125:2014, medium load size.
** Inlet water temperature 19°C, Outlet Water temperature 55°C, Dry Bulb Temperature 19°C. Accredited Testing to AS/NZS 5125 Pending by NATA accredited Provider.



Product description
The Rinnai HydraHeat® is designed primarily for outdoor installations. It may be possible to install internally if the proposed location is not an occupied space as defined by AS/NZS 5149, consult a qualified installer prior to installation.

Scope of use
Primarily designed for residential applications, but can be used for smaller commercial applications. 

Not suitable as a spa or swimming pool heater, or for hydronic applications. Hard and acidic water will need to be treated to use this product, refer water quality parameters in the support material (downloads).

Technical Specifications

Model number / order code


Storage capacity

275 L


4.7 W/W
(inlet water temp 19 ºC, outlet water temp. 55 ºC, ambient temp. 19 ºC) .

Accredited Testing to AS/NZS 5125 Pending by NATA accredited Provider.

Rated heat pump input / output

802 W / 3725 W
In standard, eco 50/55 modes, the heat pump provides 100% of the heating within the operating range. Outside these limits the electric element will operate.

Hot water recovery rate

89 L/h
Recovery rate is calculated at Eco 55 mode, 19 ºC ambient temp., 41 ºC rise.

Cylinder element rating

2 kW

Cylinder construction


Head unit data label position

Positioned on the divider panel between the fan and compressor—to the right of the control panel.

Operating temperature

-10 to 42 ºC

Noise level

45 dB(A)
Sound pressure level measured at 1 m distance from the water heater in a free field. Appliance operated in standard mode (60 ºC) at an ambient temperature of 19 ºC.

Refrigerant type

R290 / 150 g (A3 flammable)

Modes of operation
  • Standard (factory preset) water stored at 60 ºC
  • Boost, one off electric boost to 70 ºC
  • Eco 55, water stored at 55 ºC
  • Eco 50, water stored at 50 ºC 
  • High usage, water stored at 70 ºC (heat pump + electric element)
  • Element only (heat pump turned off, electric element heats water to 70 ºC
  • Shutdown (in standby, heat pump and electric element are turned off)
  • Assembled: Height - 1750 mm, diameter 692 mm
  • Heat pump header: Height 510 mm
  • Cylinder: Height 1240 mm
Water supply and connections
  • Mains pressure hot water cylinder
  • Min. inlet water pressure - 100 kPa
  • TPR (supplied) - 850 kPa
  • Cold water expansion valve - 700 kPa
  • Pressure limiting valve - 500 kPa
  • Heat pump header - 36.4 kg (net), packaged 45 kg
  • Cylinder - 77.1 kg (empty), 352.1 kg (full)
  • Full system - approx. 400 kg
IP rating

IPX4 header and cylinder

Market release

Nov 2023

MasterSpec link

CAD/BIM Downloads

Data Views
HydraHeat DWG front view
HydraHeat DWG left view
HydraHeat DWG right view
HydraHeat DWG top view